#include "my_stdio.h"
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>

mFILE *mfopen(const char *filename,const char *mode)
{
  int fd = -1;
//int open(const char *pathname, int flags);
  if(strcmp(mode,"r")==0)
  {
    fd = open(filename,O_RDONLY);
  }
  else if(strcmp(mode,"w")==0)
  {
    fd = open(filename,O_CREAT | O_WRONLY | O_TRUNC,0666);

  }
  else if(strcmp(mode,"a")==0)
  {
    fd = open(filename,O_CREAT | O_WRONLY | O_APPEND,0666);

  }
  if(fd<0) return NULL;
  mFILE* mf = (mFILE*)malloc(sizeof(mFILE));
  if(mf == NULL) {
    close(fd);
    return NULL;
  };
  mf->fileno = fd;
  mf->flag = FLUSH_LINE;//行刷新模式
  mf->size = 0;
  mf->cap = SIZE;

  return mf;
}



void mfflush(mFILE *stream)
{
  if(stream->size >0)
  {
    write(stream->fileno,stream->outbuffer,stream->size);
    stream->size = 0;
  }
}


int mfwrite(const void *ptr, int num, mFILE *stream)
{
  //1.拷贝
  memcpy(stream->outbuffer + stream->size, ptr,num);
  stream->size += num;
  
  //2.检测刷新模式
  if((stream->flag == FLUSH_LINE) && (stream->size > 0) && (stream->outbuffer[stream->size-1] == '\n'))
  {
    mfflush(stream);
  }
  return num;
}

void mfclose(mFILE *stream)
{
  if(stream->size > 0)
  {
    mfflush(stream);
  }
  close(stream->fileno);
}
